US3652814A - Reciprocating and rotatable cam actuating means for electromechanical timers - Google Patents

Abstract

In a timer switch for a timepiece the two spring biased contacts are maintained in spaced relation by means of two concentric rotatable cam members which normally bear against the flat upper surface of a timing plate having spaced-apart slots therein. Upon rotation of the cam means by the conventional time keeping gear train, the cam supporting the uppermost spring contact will drop into the spaced slots first allowing the upper spring contact to move into engagement with the lower spring contact to close the switch. Continued movement of the time keeping gear train allows the second cam supporting the lower spring contact to drop into the slot means and allow the lower spring contact to separate from the upper spring contact. Continued rotation of the cams will lift both of the cams simultaneously out of the spaced slots to restore the spring contacts to their original position while maintaining them in spaced-apart relation.

Description

United States Patent Kanazawa et al.

RECIPROCATING AND ROTATABLE CAM ACTUATING MEANS FOR ELECTROMECHANICAL TIMERS lnventors: Kozaburo Kanazawa; Eiji Kawakami, both of Tokorozawa; Yasuo Kamiyama, Yokohama, all of Japan Assignee: Citizen Watch Co., Ltd., Tokyo, Japan Filed: May 22, 1970 Appl. No.: 39,751

Foreign Application Priority Data May 23, 1969 Japan 44/40075 References Cited Morrison ..200/33 B Wiser ..200/38 B Primary Examiner-J. R. Scott Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak ABSTRACT in a timer switch for a timepiece the two spring biased contacts are maintained in spaced relation by means of two concentric rotatable cam members which normally bear against the flat upper surface of a timing plate having spaced-apart slots therein. Upon rotation of the cammeans by the conventional time keeping gear train, the cam supporting the uppermost spring contact will drop into the spaced slots first allowing the upper spring contact to move into engagement with the lower spring contact to close the switch. Continued movement of the time keeping gear train allows the second cam supporting the lower spring contact to drop into the slot means and allow the lower spring contact to separate from the upper spring contact. Continued rotation of the cams will lift both of the cams simultaneously out of the spaced slots to restore the spring contacts to their original position while maintaining them in spaced-apart relation.

2 Claims, 11 Drawing Figures PATENTEIIIIIIII28 I972 SHEET 1 [IF 2 FIG.

PRIOR ART lllllll TIME SCALE Is OPTIONAL FIG. 3

CONTACTS I4 CONTACTS l RECIPROCATING AND ROTATABLE CAM ACTUATING MEANS FOR ELECTROMECHANICAL TIMERS This invention relates to improvements in and relating to timer switch mechanism built in timepieces or time measuring instruments.

It is a general drawback in the above kind of conventional switch mechanisms that a quick breaking action can not be realized.

A further conventional drawback is a considerable fluctuation in the alarming or the like destined operation.

The main object of the invention is to provide an improved timer switch of the above kind, capable of obviating the aforementioned various conventional drawbacks.

These and further objects, features and advantages of the invention will become more apparent when read the following detailed description of the invention by reference to the accompanying drawings.

In the drawings: 7

FIG. 1 is a schematic perspective view of a comparative conventional prior art switch mechanism.

FIG. 2 is a similar view of FIG. 1, illustrative, however, of a preferred embodiment of the present invention.

FIG. 3 is a substantially sectional view of a second embodiment of the invention which has been slightly modified from that shown in FIG. 2, wherein, however, certain minor parts have been omitted for simplicity.

FIG. 4 is a plan view of an upper cam element.

FIG. 5 is a plan view of a lower cam element which cooperates with the upper cam element shown in FIG. 4.

FIG. 6 is a plan view of an unlocking cam wheel employed.

FIG. -7 A-C are exploded perspective views of the three parts shown in FIGS. 4-6.

FIG; 8, (A)-(D), are a series of explanatory sectional representations of the switching operational stages of the mechanism.

FIG. 9 is a chart showing the operational sequence of the mechanism illustrated in FIG. 8 (A)-(D).

In the following, substantially a preferred embodiment of the invention will be described in comparison with a comparative conventional switching mechanism and by reference to the accompanying drawings.

In FIG. 1 illustrating a conventional mechanism, the numeral 10 denotes a conventional unlocking wheel which is arranged to cooperate through an intermediate gear 11 with an unlocking cam wheel 12, a pair of separated positioning openings 12a and 12a being bored through the cam wheel 12 and at a certain common diametral distance measured from the center of the latter wheel. A shaft 18 extends vertically from a conventional lower plate, not shown, of a timepiece movement, again not shown, and the unlocking cam wheel 12 is rotatably mounted on the shaft. Concentrically with the cam wheel, an hour wheel assembly, generally shown at 13, is loosely mounted on the shaft, said hour wheel assembly comprising a hollow stem 13a and an hour cam wheel 13b fixedly united together. On the bottom surface of the hour cam wheel 13b, there is fixedly provided a pair of cam projections 13d and 13d having a mutual circumferential pitch equal to that defined between the positioning openings 12a and 12a, the cam projections being adapted for occasional engagement with the openings 12a and 12a.

A stationary mount 90 made of an insulating material is fixedly mounted on the lower plate and mounting thereon in turn a movable spring contact 140 and a stationary spring contact 140' by embedding or screwing their root portions in or to the material of the mount 90. These spring contacts 140 and 140' are shaped into hooks as shown and the upper or movable contact 140 is so designed and arranged that the bent or sharply curved portion of the hook is kept normally in pressure contact with the upper surface of stem 13a for urging the hour wheel assembly 13 to move downwards in FIG. 1. Contacts 140 and 140' are electrically connected with leads 91 to a certain electric circuit (not shown) to be controlled and a power source (not shown) therefor, although not specifically shown.

When the unlocking wheel 10 is rotated manually in the direction shown by a small arrow, motion is transmitted therefrom through intermediate gear 11 to unlocking cam wheel 12, thereby the latter being rotated in counter clockwise direction in FIG. 1 until an aimed alarm time is preset.

Then, motion is transmitted from the conventional hour hand wheel 119 of time-indicating gear train constituting the movement of the timepiece, to hour wheel assembly 13 so as to rotate the latter in clockwise direction in FIG. 1 or in the opposite direction to the rotational direction of the unlocking cam wheel 12. By virtue of the relative rotational movement of the said both, the cam projections 13d and 13d will approach towards the engageable openings 12a and 120, respectively. Upon lapse of a certain time, the cam projections are brought into engagement with the respective engageable openings so that the assembly 13 is urged by the resilient pressure exerted by the upper spring contact to slide axially and downwardly, thereby the upper spring contact being brought into contact with the lower spring contact 140'. Thus, the desired electric closure of the switching mechanism is realized.

With further rotation of the assembly 13 by being driven from the time-indicating gear train, the cam projections 13d and 13d will disengage from the respective openings 12a and 120', respectively and the upper and lower contacts 140 and 140' are gradually disengaged from contact with each other and finally the switch is brought into its open condition as before.

Therefore, it will be seen that with use of the aforementioned conventional switching mechanism, a desirous quick interruption or an instantaneous return movement of the movable contact can not be realized. In addition, the operation period is relatively indefinite and thus non-reliable.

Next, referring to FIG. 2, a preferredembodiment of the invention shown only schematically will be described in detail.

In this figure, 10' denotes an unlocking wheel similar to that shown at 10 in FIG. 1, which is provided for presetting manually any desired alarm time point. 15 represents generally an unlocking cam wheel which is rotatably mounted on a vertical shaft 18 extending rigidly from the lower plate (see, also FIG. 3), said wheel 15 being kept in direct engagement with the unlocking wheel 10. The unlocking cam wheel 15 is formed with a pair of somewhat elongated and curved slots 15a and 15a (see also FIGS. 6 and 7C) having different diametral distances and preferably different peripheral lengths from each other.

On the vertical shaft 18 and thus concentrically with and above the unlocking cam wheel 15, a first cam element 16 substantially in the outline form of a gear is rotatably mounted and meshing with a conventional hour hand wheel 19 arranged to be driven by the time-indicating gear train.

The first cam element 16 is formed with a concentric hollow cylinder 16c (see also FIG. 7B) and a pair of cam projections 16a and 16a rigid with the cam wheel proper and each having a substantially triangular shape, when seen in FIG. 8 at (A). The first cam wheel 16 is further formed with a pair of positioning segmental slots 16b and 16b as shown in FIG. 7B.

The cam projection 16a, more specifically, depends from the bottom surface of the lower or first cam element 16 and is adapted for engagement with the first slot 15a. In the similar way, the other cam projection 16a is arranged for occasional engagement with the remaining cam slot 15a. As seen especially from FIG. 5, the cam projections 16a and 16a are positioned in close proximity to the segmental slots 16b and 16b, respectively.

Cam projections 16a and 16a are arranged in diametral opposition to each other, while positioning slots 16b and 16b are positioned again in diametral opposition to each other, as shown in FIG. 5.

As most clearly be seen from FIGS. 4 and 7A, the upper or second cam element 17 comprises a ring 170 having an internal diameter so as to be slid onto the cylindrical part of the lower cam element 16 and is formed with a pair of separated positioning projections 17b and 17b, each having an overall configuration and dimension so as to be slid into segmental openings 16b and 16b, respectively. The assembled relative position of these three parts 15, 16 and 17 rotatably supported on the shaft 18 may most clearly be seen from FIG. 3 by consultation with F lG. A-D.

Now returning to FIG. 2, there are provided a movable spring contact 14 and a spring contact 14' which are similar to those shown at 140 and 140, respectively in FIG. 1, said both contacts being fixedly mounted as before on an insulating mount 20 which is similar in its design and function to that shown at 90 in FIG. 1. Electric leads 105 similar to those at 91 are also provided. It should, however, be noted that the corresponding parts 14, 14, 20, 103 and 104 are somewhat modifiedly arranged in FIG. 3 from FIG. 2.

More specifically, the fixing bolt 103 in FIG. 3 passes through movable contact 14, insulating separator 104, stationary contact 14' and the central bore at 20a of mount 20, said bolt having threaded part 103a screwed into a tapped hole 102a bored through the lower plate at 102. The opening in contact 14' through which bolt 103 passes is sufficiently large as shown at 104 to prevent electrical contact therebetween to eliminate any possibility of an electrical short.

The movable contact 14 is shaped again into a hook and kept into pressure contact with the upper surface of cylindrical stem 160 so as to urge the first cam element 16 for downward movement thereof, and the equally hook-shaped contact 14' is kept into pressure engagement with the upper surface 170 of upper cam element 17.

Contacts 14 and 14 are provided at their respective ends with hard contacting elements 14a and 14a, respectively, as known per se.

The operation of the switching mechanism is as follows:

For the presetting service so as to establish a predetermined alarm time point, the unlocking wheel is manually turned as desired, as was referred to with relation to FIG. 1 concerning the wheel 10, so as to turn the cam wheel to a certain point. In this way, slots 15a and 150' are positioned for the aimed alarm service and relative to cam projections 16a and 16a,

Then, rotation is transmitted from the hour hand wheel 19 to the first cam element 16 so as gradually turn the later in the clockwise direction. In the position shown in F IG. 2, both contacts l4 and 14' are separated from each other and thus the switching mechanism is in its interrupted or off"-position, corresponding the stage O-A in F IG. 9.

Upon lapse of the preset time period, cam projections 16a and 16a are brought into engagement with slots 15a and 15a, respectively and the spring urging pressure exerted by the movable contact 14 becomes effective to urge the cam element 16 for downward movement thereof and at the same time, the movable contact proper 14a is brought into contact with the mating contact point 14a so that the switching mechanism changes over to its on"-position.

Since the contact 14' exerts even at this stage a resilient urging pressure on the upper surface 17c of the cam member 17, the projections 17b and 17b are kept in their pressurized abutting condition upon the upper surface of the cam wheel 15, even after the thus established engaging condition between projections 16a; 16a and respective slots 15a; 15a, as shown in FIG. 8(B).

In this way, the upper surface 16d of cam member 16 and the upper surface of the member 17 will approach towards each other and contacts proper 14a and 14a are brought together into pressure contact, so that the circuit to be controlled is closed.

With further rotation of cam element 16, cam projections 17b; 17b are brought into engagement with slots 15a; 15a, respectively, thus the lower contact being lowered in its position and the hitherto established contact between contact points 14a and 14a being instantly released by the action of the spring force.

The above stage corresponds to B-C in F IG. 8.

The contacting stroke of the spring contacts 14a and 14a is determined by the distance between the slots 16b and 16b. Therefore, it is recommendable to provide variously dimensioned cam elements 16 for specific operational services, adapted for use, as an example, in 30 minutes, hour, 2 hour services, respectively.

With still further rotation of cam element 16, cam projections 16a; 16a will commence to recede from engagement with respective slots 15a; as shown in FIG. 8(D). At this stage, the relationship between the contacts 14 and 14' is such that the upper spring contact 14 exerts a downward urging pressure upon the upper surface 16d of cam element 16. Although, at this stage, the lower spring contact 14' is kept in pressure contact with the upper surface 17c of cam element 17, the mutual distance between the cam elements 16 and 17 is not altered, because cam projections 16a; 16a will only slide along the upper surface of the unlocking cam wheel 15 with continued rotational movement of the cam element 16. Therefore, an undesirous contact between contact springs 14a and 14a is positively prevented.

When hour cam element 16 has been turned 360, cam projections 16a and 16a will be brought again into engagement with the respective reception openings.

It will be seen from the foregoing that there is provided each pair of slots 15a; 15a, cam projections 16a; 16a, positioning slots 16b; 16b, and cam projections 17b; 17b, which serves for the prevention of any relative inclination between the cam elements 16 and 17. In this way, an accurate cooperation between hour hand wheel 19 and hour cam 16 will be positively assured and the on-off control operation of the movable height H of cylindrical stem 16c of cam element 16 minus the thickness h of the ring part of the element 17. Therefore, the contact points 144 and 14a is kept in separation from each other.

Upon a rotation of cam member 16 from the starting point A, as shown in FIG. 9, 16a; will drop into the respective slots 15a; 15a. The contact point 14a will be lowered by a distance, shown in FIG. 3, which corresponds to the height of each of cam projections 16a,- 16a. Naturally, L must be larger than h". In FIG. 8 (A) and (C), the contact 14 is substantially stabilized.

In FIG. 8, (A) represents the open stage of the mechanism, while (B) represents its closing stage where the operation is abruptly and suddenly performed.

Under the normal state at 0 of the switching mechanism, the both contacts 14 and 14' are positioned in contact respectively with the cam elements 16 and 17. The mutual distance is defined by h" which equals to a difference between the symbols 15" and F" of FIG. 9 correspond respectively to the tip contacting ends of the spring contacts 14 and 14'. Furthermore when the first cam element 16 is rotated to B point, the positioning projections 17b and 17b of the second cam element 17 are urged against the side wall of the slots 16b and 16b of the first cam element 16 to drop the positioning projections 17b and 17b into slots 15a and 15a, as shown in FIG. 8(C), the stationary contact 14a to be lowered by the height of h to restore instantaneously to the normal space (H). Consequently, contacts 14a and 14a are disengaged to return to the original position. C point shows the condition under which cam projections 16a and 16a emerge from the slots 15a and 15a of the unlocking cam wheel 15. At the next points D, the cam wheels 15 and 16 and cam element 17 return to the starting point 0. Since the interval between A and B points is instantaneously switched, the precise interval for switching operation time can be obtained, as well as the precise duration of the time the contacts are closed, the time period B-C, due to the cam element 17. a

The embodiments of the invention in which as exclusive property or privilege is claimed are as follows:

1. A timer controlled switch assembly comprising, a rigid base member having a support shaft rigidly attached thereto, an unlocking cam wheel rotatably mounted on said support shaft, said unlocking wheel being operatively connected with a manually rotatable time setting wheel, said unlocking cam wheel having a plurality of camming slots formed on a side surface thereof, each of said camming slots being of a predetermined arcuate length and being positioned at a different radial distance from the center of said unlocking cam wheel, a first cam element rotatably supported on said support shaft adjacent said unlocking cam wheel, the surface of said first cam element facing said unlocking cam wheel having a plurality of cam projections formed thereon, said cam projections corresponding, respectively, with each of said camming slots formed in the adjacent surface of said unlocking cam wheel, said first cam element further including a plurality of segmental slots formed therethrough, each of said segmental slots positioned adjacent the projected end portions of said cam projections, a concentric hollow cylinder secured to the surface of said first cam element opposite said cam projections and positioned concentrically around said support shaft, said concentric cylinder having an end surface for supporting a first electrical contact, said first cam element being operatively connected to and rotatably driven by a gear of a time-indicating gear train means, and a second cam element supported by said hollow cylinder portion of said first cam element and axially movable thereon, said second cam element having a plurality of positioning projections formed on the side thereof adjacent said first cam element, said positioning projections corresponding to and extending through said segmental openings of said first cam element, the lengths of said positioning projections of said second cam element corresponding to the the lengths of said cam projections of said first cam element when said first and second cam elements are in an abutting relationship with each other, the axial length of said second cam element being less than the axial length of said concentric hollow cylinder of said first cam element, the surface of said second cam element opposite said positioning projections supporting a second electrical contact corresponding to said first electrical contact for operative contact therewith to establish an electrical connection therebetween, said electrical contact being obtained between said first and second electrical contacts upon the expiration of a preset time period established by the rotation of said unlocking cam wheel by said unlocking wheel, the cam projections of said first cam element engaging said corresponding slots in said unlocking cam wheel to cause said hollow cylinder of said first cam element to move axially toward said second cam element to bring said first electrical contact into engagement with said second electrical contact, said electrical connection being maintained for a predetermined length of time depending upon the areaate length of said positioning projections of said second cam element, said positioning projections of said second cam element moving into engagement with said segmental slots of said unlocking cam wheel to cause said second cam element to move axially away from the end surface of said hollow cylinder to separate said first and second electrical contacts.

2. A timer controlled switch assembly as recited in claim 1, wherein the distance between said first and second electrical contacts is substantially equal to the axial length of said hollow cylinder minus the thickness of said second cam element.

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Claims (2)

1. A timer controlled switch assembly comprising, a rigid base member having a support shaft rigidly attached thereto, an unlocking cam wheel rotatably mounted on said support shaft, said unlocking wheel being operatively connected with a manually rotatable time setting wheel, said unlocking cam wheel having a plurality of camming slots formed on a side surface thereof, each of said camming slots being of a predetermined arcuate length and being positioned at a different radial distance from the center of said unlocking cam wheel, a first cam element rotatably supported on said support shaft adjacent said unlocking cam wheel, the surface of said first cam element facing said unlocking cam wheel having a plurality of cam projections formed thereon, said cam projections corresponding, respectively, with each of said camming slots formed in the adjacent surface of said unlocking cam wheel, said first cam element further including a plurality of segmental slots formed therethrough, each of said segmental slots positioned adjacent the projected end portions of said cam projections, a concentric hollow cylinder secured to the surface of said firsT cam element opposite said cam projections and positioned concentrically around said support shaft, said concentric cylinder having an end surface for supporting a first electrical contact, said first cam element being operatively connected to and rotatably driven by a gear of a time-indicating gear train means, and a second cam element supported by said hollow cylinder portion of said first cam element and axially movable thereon, said second cam element having a plurality of positioning projections formed on the side thereof adjacent said first cam element, said positioning projections corresponding to and extending through said segmental openings of said first cam element, the lengths of said positioning projections of said second cam element corresponding to the the lengths of said cam projections of said first cam element when said first and second cam elements are in an abutting relationship with each other, the axial length of said second cam element being less than the axial length of said concentric hollow cylinder of said first cam element, the surface of said second cam element opposite said positioning projections supporting a second electrical contact corresponding to said first electrical contact for operative contact therewith to establish an electrical connection therebetween, said electrical contact being obtained between said first and second electrical contacts upon the expiration of a preset time period established by the rotation of said unlocking cam wheel by said unlocking wheel, the cam projections of said first cam element engaging said corresponding slots in said unlocking cam wheel to cause said hollow cylinder of said first cam element to move axially toward said second cam element to bring said first electrical contact into engagement with said second electrical contact, said electrical connection being maintained for a predetermined length of time depending upon the arcuate length of said positioning projections of said second cam element, said positioning projections of said second cam element moving into engagement with said segmental slots of said unlocking cam wheel to cause said second cam element to move axially away from the end surface of said hollow cylinder to separate said first and second electrical contacts.

2. A timer controlled switch assembly as recited in claim 1, wherein the distance between said first and second electrical contacts is substantially equal to the axial length of said hollow cylinder minus the thickness of said second cam element.

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